Multi-wavelength NIR system for spectroscopy of biomedical tissues
ABSTRACT A custom designed optical system is reported for tissue spectroscopy over four wavelengths of 677 nm, 780 nm, 830 nm, and 977 nm. A high speed laser driver is designed with a flat frequency response using pre-emphasis circuit. The driver is employed for high current in high power lasers. Phantom and intra-lipid experiments are performed to extract optical parameters of a turbid media. Broadband measurement is used to extract optical parameters of the phantom model simulating a breast tissue using forward scattering models. The optical parameters () are extracted with a very good accuracy.
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- "An investigation into the effects of static background structure on the images of change in optical properties was presented. Mu et al. (2003) reported that phantom and Intra-lipid experiments were performed to extract optical parameters of a turbid media. Broadband measurement was conducted to extract optical parameters of the phantom model simulating breast tissue using forward scattering models. "
ABSTRACT: Diffuse optical tomography (DOT) is a new tomographic technique, which is non-invasive and does not involve radiation exposure. In this paper, a self-developed near infrared (NIR) diffuse optical tomography instrument is described, and phantoms com-posed of Intra-lipids are discussed. The NIR optical characteristics of the homogenous Intra-lipid phantoms are measured to construct a set of databases at various concentrations, and further analysis using fitting curves is presented as well. Additionally, a pseudo-model technique for imitating biological tissues is proposed and implemented. This pseudo-model can be used to represent the same optical characteristics as real tissues, meaning that it is a viable alternative to cope with measuring limitations. Experiments reveal good results when the pseudo-model employs 1% Intra-lipid as a background tissue that imitates pork and 3% Intra-lipid as an inclusion to mimic a bone. Due to the limitations of hardware nowadays, obviously, this pseudo-model will offer a great aid for the development and evaluation of a DOT system.Journal- Chinese Institute of Engineers 03/2007; 30(2). DOI:10.1080/02533839.2007.9671245 · 0.21 Impact Factor
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ABSTRACT: Microwave Photonics techniques are applied to functional near IR (fNIR) imaging systems, where absorption and scattering parameters of tissue is extracted using multi-wavelength spectroscopy. Clinical applications of fNIR systems to anesthesia and wound healing are also discussed.Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 01/2009; DOI:10.1109/LEOS.2009.5343362
Conference Paper: RF and Microwave Photonic techniques in biomedical applications[Show abstract] [Hide abstract]
ABSTRACT: This invited paper addresses various "microwave photonics" techniques developed for biomedical applications. The first application is using RF photonics technique for calibration of ultrasound transducers operating at high-frequencies without spatial field averaging compromise. In particular a broadband fiber-optic based hydrophone probe is reported for measurements of acoustic fields at the frequencies up to 100 MHz. In another application of microwave photonics, tissue spectroscopy is performed using multi-wavelength absorption and scattering in near infrared. A high speed and high power laser driver is designed with a flat frequency response using RC speed up circuits in high power lasers. Phantom experiments are performed to extract optical parameters. Multi-frequency data fitting algorithm is performed to extract optical parameters of the phantom model simulating a breast tissue. The optical parameters (mua, mus') are extracted with a very good accuracy. These low cost techniques are replacement for other expensive sub-centimeter spatial resolution medical imaging methods.Sarnoff Symposium, 2009. SARNOFF '09. IEEE; 05/2009